Nemaha County, Nebraska: History
The county forms the core of the Nemaha Half-Breed Reservation formed in the Fourth Treaty of Prairie du Chien in 1830 as land for the offspring of traders and Native Americans. The grounds of modern Indian Cave State Park mark where the county's first community, Saint Deroin, was founded in 1853 by members of the reservation as a trading post on the Missouri River. When white settlement was permitted in the Kansas–Nebraska Act of 1854, this area was part of Forney County (named for US cabinet member John W. Forney) which stretched along the Little Nemaha River from the Missouri River to west of Lincoln, Nebraska. In 1855 Nemaha County was formally founded with Brownville as its county seat. Johnson County, also founded in 1855, was initially administratively attached to Nemaha, but was organized as a stand-alone county in 1857.
Brownville was the biggest city in Nebraska at the time and several firsts occurred in the county including: in 1861 the first state normal school was founded at what today is Peru State College; Daniel Freeman filed the first claim under the Homestead Act of 1862 for land on January 1, 1863, at the Brownville land office.
The Nebraska State Fair was held in the county at Brownville in 1870–1871.
In 1883 the county seat was moved to Auburn.
In 1974 the Cooper Nuclear Station was commissioned south of Brownville.